Following a meeting with London Underground, the rail union has agreed that no drivers would be forced to work longer hours.

Under the agreement some drivers will do five round trips in the course of a weekday shift, rather than the current four – but this will not increase working hours.

London Underground’s chief operating officer, Howard Collins, said: “There was never any reason for this strike threat. No driver is being asked to work longer hours. We will simply be asking some drivers to do another round trip, so five round trips are undertaken, as they already are at weekends.

“The change in working patterns, which had already been accepted by Aslef, follows improvements we have made to working conditions, including air cooling in drivers’ cabs.”